The turbine-type flow meter has been used for many years in the measurement of fluids. Interest in this type of meter has greatly increased in recent years. One of the reasons for this increased interest is the proven reliability of the turbine type flow meter when it is correctly designed and properly applied. It has a high degree of repeatability when the meter operates within its normal range and when it is in good physical condition.
It is generally accepted in the gas industry that the accuracy of gas turbine meters is established by calibration, usually in the manufacturer's facility. Once a meter has been calibrated, it is important to have some method which can determine whether this accuracy is being maintained in the field.
The best way for the meter user to check the meter accuracy is to have a calibration stand of his own. However, in order to utilize a calibration stand, the meter (or at least the measuring rotor) must be removed from the service line in which it is installed. This is not always convenient, or even possible at some times.